Yours is the first deployment I've seen of that term. I prefer to use the term "resistant training" and many people say "live" training.
In yoseikan, we had shite randori, with set attacks and defenses, jiyu randori, with completely free attacks, and chikara randori, meaning free attacks and defenses, with uke giving continuous, strong follow up attacks if nage does not effect a decisive response in the first instant of the attack. If the attacker doesn't have to fall, he does not and continues the attack. This often went to the ground and newaza, frequently ending in a choke or strangulation. And remember that the yoseikan randori was full of sutemi waza, multiple opponents, bokken, padded pvc swords, knives, bo, etc. I never saw anyone use throwing stars or the claw hands, but most everything else.
It was cooperative, yet when two people were grappling on the ground, they were cooperating by giving the partner a tough opponent intent on choking him out or submitting him. It was basically the same as UFC but without bloodying each other up too much. We placed atemi but generally didn't strike each other heavily. And if you didn't throw someone who punched at you, he might follow up with a foot sweep and attempt to apply a joint lock of a wide variety.
What we cooperated in was a universal commitment to a powerful, meaningful attack allowing nage to develop first-instant throwing or joint-locking--not meaning that the joint is locked in the first instant, but the lead into the lock is established in the first instant, creating kuzushi and control for nage. It was intense and dangerous. And it took cooperative commitment to that danger, courage and calmness to move in it at high speed with lots of people and weapons, and commitment to the well-being of your partner, with the rule of never doing more than necessary to stop a violent person--but stopping him decisively.
Cooperative or uncooperative, whatever you would call it, that was real aikido and, as far as I'm concerned, the only meaningful progression to develop true technique. The internal power considerations are another matter.
I would suggest "kata-only" for those practices in which uke purposely moves in the way he is "supposed" to move, rather than how his reflexes advise him. In "kata-only" training, neither uke nor nage gives any resistance to the other or to the mutual performance of the kata that each technique is.
I can see value in that kind of practice maybe 5% of total time, with another 20% being actual kata training, such as Mochizuki's tai sabaki no kata or his hyori no kata; or Tomiki's "walking" kata and others, such as junana no kata. Another 25% being intense kihon waza training and 50% being randori. The randori levels would increase with the student's experience, with shite or designated randori early on, jiyu randori nearing black belt and chikara randori after that, at which time randori should be liberally peppered with sutemi waza. Under Mochizuki, we regularly did hour-long sutemi-only chikara randori.
So that type of training would fall under what I prefer to term "live" practice.
I would recommend some "kata-only" training from the beginning, with more and more "resistance" from uke when nage's technique leaves that possibility.
Two major points:
In "kata-only" practice, neither uke nor nage resists the other's efforts.
In "live" practice, uke may resist with strength, speed and technique if he can find an opportunity; but nage's training is to move in such a way that he never resists uke in any way, so that uke can find no strength to resist and all his efforts fall into nothing.
Again, this does not address questions of internal power development or use. This is just the omote form of technical aikido training. I do believe that IP/Aiki would make it much easier to bear training of that kind while making every technique a living thing, rather than a form (kata).
But for training solid aikido technique and application, the "cooperation" of uke and nage must be a commitment to development of instant aikido technical effectiveness against a strong and "live" uke, committed to an effective attack.